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  <h1 class="topictitle1">Threads</h1>
 
  
  <div> 
	 <div class="section"> 
		<p>Intel&reg; Threading Building Blocks (Intel&reg; TBB)
		  provides a wrapper around the platform's native threads, based upon the N3000
		  working draft for C++11. Using this wrapper has two benefits:
		</p>
 
		<ul type="disc"> 
		  <li> 
			 <p>It makes threaded code portable across
				platforms.
			 </p>
 
		  </li>
 
		  <li> 
			 <p>It eases later migration to ISO C++11
				threads.
			 </p>
 
		  </li>
 
		</ul>
 
		<p>The library defines the wrapper in namespace 
		  <samp class="codeph">std</samp>, not namespace 
		  <samp class="codeph">tbb</samp>, as explained in Section Namespace.
		</p>
 
		<p>The significant departures from N3000 are shown in
		  the table below. 
		</p>
 
		
<div class="tablenoborder"><a name="tbl36"><!-- --></a><table cellpadding="4" summary="" id="tbl36" width="100%" frame="hsides" border="1" rules="all"><caption><span class="tablecap">Differences Between N3000 and Intel&reg; TBB
		  Thread Class</span></caption> 
		   
		   
		  <thead align="left">
			 <tr> 
				<th class="cellrowborder" valign="top" width="NaN%" id="d123197e64"> 
				  <p>N3000
				  </p>
 
				</th>
 
				<th class="row-nocellborder" valign="top" width="NaN%" id="d123197e70"> 
				  <p>Intel&reg; TBB
				  </p>
 
				</th>
 
			 </tr>
</thead>

		  <tbody> 
			 <tr> 
				<td class="cellrowborder" valign="top" width="NaN%" headers="d123197e64 "> 
				  <p><samp class="codeph">template&lt;class Rep, class
						Period&gt; std::this_thread::sleep_for(</samp>
				  </p>
 
				  <p><samp class="codeph">const chrono::duration&lt;Rep,
						Period&gt;&amp; rel_time)</samp>
				  </p>
 
				</td>
 
				<td class="row-nocellborder" valign="top" width="NaN%" headers="d123197e70 "> 
				  <p><samp class="codeph">std::this_thread::sleep_for(
						tick_count::interval_t )</samp>
				  </p>
 
				</td>
 
			 </tr>
 
			 <tr> 
				<td class="cellrowborder" valign="top" width="NaN%" headers="d123197e64 "> 
				  <p>rvalue reference parameters
				  </p>
 
				</td>
 
				<td class="row-nocellborder" valign="top" width="NaN%" headers="d123197e70 "> 
				  <p>Parameter changed to plain value, or
					 function removed, as appropriate.
				  </p>
 
				</td>
 
			 </tr>
 
			 <tr> 
				<td class="cellrowborder" valign="top" width="NaN%" headers="d123197e64 "> 
				  <p>constructor for 
					 <samp class="codeph">std::thread</samp> takes arbitrary number of
					 arguments.
				  </p>
 
				</td>
 
				<td class="row-nocellborder" valign="top" width="NaN%" headers="d123197e70 "> 
				  <p>constructor for 
					 <samp class="codeph">std::thread</samp> takes 0-3 arguments.
				  </p>
 
				</td>
 
			 </tr>
 
		  </tbody>
 
		</table>
</div>
 
		<p>The other changes are for compatibility with the
		  current C++ standard or Intel&reg; TBB. For example, constructors that have an
		  arbitrary number of arguments require the variadic template features of C++11.
		</p>
 
		<div class="Note"><h3 class="NoteTipHead">
					Caution</h3> 
		  <p>Threads are heavy weight entities on most
			 systems, and running too many threads on a system can seriously degrade
			 performance. Consider using a task based solution instead if practical. 
		  </p>
 
		</div> 
	 </div>
 
  </div>
 
  
<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong>&nbsp;<a href="../reference/reference.htm">Intel&reg; Threading Building Blocks Reference Manual</a></div>
</div>
<div class="See Also">
<ul class="ullinks">
<li class="ulchildlink"><a href="../reference/threads/thread_cls.htm">thread Class</a><br>
</li>
<li class="ulchildlink"><a href="../reference/threads/thread_id.htm">thread::id</a><br>
</li>
<li class="ulchildlink"><a href="../reference/threads/this_thread_namespace.htm">this_thread Namespace</a><br>
</li>
</ul>

<h2>See Also</h2>
<div class="linklist">
<div><a href="general_conventions/namespaces.htm">Namespaces, std Namespace 
		  </a></div></div>
</div>

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